The present invention relates broadly to a multi-element or mosaic antenna structures, and in particular to a hub and petal configuration for large mosaic mirrors and millimeter wave antennas.
The state of the art of large multi-element antennas are well represented and alleviated to some degree by the prior art apparatus and approaches which are contained in the following U.S. Patents:
U.S. Pat. No. 3,378,469 issued to Jochim on Apr. 16, 1968;
U.S. Pat. No. 3,428,533 issued to Pichel on Feb. 18, 1969; and
U.S. Pat. No. 4,740,276 issued to Marmo et al on Apr. 26, 1988.
The Jochim patent describes a method of simultaneously providing the backing or rigidizing structure which is also electroformed, and the electroformed device itself, whether it be a mirror or some other device. This is done by halting the electroplating of the device before it is finished and applying a properly shaped mesh to it. The electroplating process is then continued so that the mesh becomes permanently affixed to and becomes an integral part of the device being electroformed, thereby providing the backing structure for it in substantially the same step in which the device is formed.
The Pichel patent discloses a method of casting a plastic sub-master from a glass master. A layer of nickel is deposited over the plastic sub-master to provide a metal replica. A structure is mounted onto the metal replica to rigidize it. The rigidized replica is then parted from the sub-master, after which a hard surface, such as a rhodium or chromium surface, is plated over the nickel face of the replica to provide it with a scratch and abrasion resistant surface. At this point, the rigidized metal replica may be utilized instead of the glass master and as many plastic submasters made from it as may be needed.
The Marmo et al patent is directed to a method of electroforming a continuous faceplate which contains coolant channels just below the optical surface. The continuous faceplate is bonded to a rigidized substrate to prevent distortion of the faceplate during or after separation from a master. A circular ring land on the rear surface of the individual master segments greatly provides improved segment alignment and rigidity over prior art mounting surfaces.
While the above-cited prior art patents are instructive, it is clear that a need remains to provide large mosaic mirrors and millimeter wave antennas which solves the shortcomings of the prior art. The present invention is intended to satisfy that need.